Heavy-Duty Plastic Picture Hanger Having Dual-Hooks And Hook-Above-Nail Arrangements

ABSTRACT

Present invention discloses a heavy-duty plastic hanger that has both dual-hooks and hook-above-nail arrangements, and offers a 50 lb. or 70 lb. weight load capacity with two or three 3d penny size finish nails anchoring the hanger onto drywall at 15 degree incline angle.

BACKGROUND OF THE INVENTION

Now day, user commonly uses a pair of metal hangers to hang a largepicture frame on wall. Before hanging the picture frame, user needs toadopt a leveling tool (i.e. spirit level) to mark a horizontal line onwall, and then anchor the metal hangers along the horizontal line. Afterhanging the picture frame, user needs to take time and effort to adjustpicture frame to a level and balance position. This is because pictureframe can't be hung in level and balance if its weight center (i.e.center line) is not positioned nearby the center location betweenhangers.

There is one major drawback of metal hanger of prior art. It typicallyhas a nail-above-hook arrangement, in which, a lateral projectile isprovided directly above hook for guiding nail into wall in inclineposition. When user is holding picture frame above hanger in an attemptto hang the picture frame, he needs to maneuver the metal wire ofpicture frame to bypass the lateral projectile while sliding pictureframe against wall in downward direction. Afterward, he needs tomaneuver the metal wire into the hook that is immediately below thelateral projectile. Many users consider such maneuver task troublesomeand user-unfriendly.

Using metal hanger in lieu of plastic hanger also has two obviousdisadvantages: (1). Metal hanger has higher material and manufacturingcosts. (2). Metal hanger is vulnerable to corrosion, particularly,metal-to-metal contact corrosion between the metal body of hanger andthe metal wire of picture frame. Unfortunately, plastic hangers of priorart characteristically have limited load capacity due to the inherentlow-shear/bending-strength plastic material characteristics.

The motivated concept of present invention is to improve structuraldesign of plastic hanger, and provide a plastic hanger that not only hasdual-hooks and hook-above-nail arrangements, but also has a loadcapacity equivalent to that of metal hangers. The above hanger becomesmore user friendly because:

(1). There is no need to adopt a leveling tool (i.e. spirit level). (2).There is no need to mark a horizontal line on wall for installinghangers. (3). Troublesome maneuver task for engaging metal wire ofpicture frame into hook is eliminated. (4). Adjusting picture frame in alevel and balance position takes less effort and time. This is becausehanger is provided with a marking along the vertical centerline ofhanger, and user can visualize it as a target while aligning the weightcenter (i.e. center line) of picture frame to the center locationbetween hangers (i.e. dual-hooks). In prior art, when a pair of hangersare installed and separated at a distance on wall, user can't visualizethe center location between hangers unless he takes time and effort totake measurement and mark it on wall.

By conducting extensive mechanics analyses and load testing ofprototypes, author of present invention is able to achieve thestructural design of hanger of present invention that has bothdual-hooks and hook-above-nail arrangements, and offers a 50 lb. (or 70lb.) weight load capacity with two (or three) nails anchoring hangeronto drywall, that is equivalent to the load capacity of asingle-hook-dual-nails metal hanger of prior art, or the load capacityof a pair of single-hook-single-nail metal hangers of prior art. Someimportant design features of hanger of present invention are discussedin detail in later section.

In U.S. Pat. No. 5,178,355, Herzig discloses a hanger withhook-above-nail arrangement. Herzig's hanger has a vertical lower body,an inclined upper body, and an inclined nail hole penetrating upper bodyalong the longitudinal center line of upper body. Top surface of upperbody is divided into a rear inclined top surface for hanging a metalwire of picture frame, and a front horizontal top surface for supportinga small L-shaped metal frame of picture frame.

Herzig's hanger has a major drawback that metal wire of picture caneasily fall off from top surface of upper body. Herzig's hanger is lackof all the design features of hanger of present invention as discussedin later section. An ordinary designer may modify Herzig's hanger toeliminate the above drawback, but he can't possible modify Herzig'shanger to achieve a load capacity equivalent to that of hanger ofpresent invention. This is due to the fact that, in order to achieveload capacity of hanger of present invention, ratio of “the height ofnail exit above bottom edge of lower body” to “the lateral width of opentop surface” needs to be equal to or greater than 530%. This designfeature of hanger of present invention is based on mechanical analysesand load testing, and can't possibly be comprehended or suggested by anordinary designer without conducting mechanics analyses and loadtesting.

We may argue that load capacity of Herzig's hanger can be increased byproportionally enlarging its size without modifying its structuraldesign. In this case (without implementing all the design features ofhanger of present invention), the enlarged Herzig's hanger can'tpossibly achieve a structural strength equivalent to that of hanger ofpresent invention, so that the enlarged Herzig's hanger can't possiblyachieve a load capacity equivalent to that of hanger of presentinvention. Also in this case, overall width of Herzig's hanger willincrease proportionally, and thus create a large gap between wallsurface and rear surface of picture frame while hanging the pictureframe on wall. This is not acceptable because we all know that overallwidth of hanger needs to be restricted in order to eliminate or minimizesuch a gap.

In U.S. Pat. No. 7,216,841, Dodig discloses a hanger with dual-hooksarrangement. In first embodiment, hanger has a nail-above-hookarrangement. In second embodiment, hanger has a hook-above-nailarrangement. Dodig's hanger is inherent with low shear/bending strengthplastic material characteristics. Without implementing all the designfeatures of hanger of present invention, Dodig's hanger is deemed to bea light-duty hanger for hanging a small picture frame.

SUMMARY OF THE INVENTION

Objective of present invention is to provide a plastic hanger that hasboth dual-hooks and hook-above-nail arrangements, and offers a loadcapacity equivalent to that of a pair of single-hook-single-nail metalhangers, or a single-hook-dual-nails metal hanger.

Another objective of present invention is to provide such a plastichanger with a minimum overall width that minimizes the gap between wallsurface and rear surface of picture frame while hanging picture frameonto wall.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective and exploded view of the first preferredembodiment of hanger of present invention.

FIG. 2 is a cross sectional view of FIG. 1.

FIG. 3 is a perspective view of the second preferred embodiment ofhanger of present invention.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective and exploded view of the first preferredembodiment of hanger of present invention, in which, hanger 1 comprisesof a base plate 2, and a pair of identical left and right lateralprojectile 3 and 4 integrally connected to base plate 2.

In FIG. 1, base plate 2 is divided into a left rectangular section 5, acentral rectangular section 6, and a right rectangular section 7, inwhich, left section 5 has a height, width or surface area identical tothat of right section 7, but smaller than that of central section 6.Central section 6 is divided into an upper portion 8 above the height ofleft or right section, and a lower portion 9 below the height of left orright section.

Left lateral projectile 3 or right lateral projectile 4 is integrallyconnected to left section 5 or right section 7 of base plate 2 to form ahanger body 10 as shown in FIG. 2. In FIG. 2, hanger body 10 comprisesof a lower body 11, a transition body 12 projecting upwardly andforwardly from lower body 11, and an upper body 13 projecting upwardlyfrom the front portion of transition body 12.

Lower body 11 has a bottom surface 14, a vertical rear surface 15emerging from the bottom edge 16 of lower body 11, and a vertical frontsurface 17. Rear surface 15 is flush to a vertical rear surface 18 oftransition body 12. The combined rear surfaces 15 and 18 have a height,width or surface area identical to that of left or right section of baseplate 2.

Transition body 12 has an inclined bottom surface 19 sloping upwardlyand forwardly from the adjacent front surface 17 of lower body 11, asubstantially vertical front surface 20, and an inclined open topsurface 21 sloping upwardly and forwardly from rear surface 18. Inclinedopen top surface 21 is flush to top surface 22 of left or right sectionof base plate 2.

Transition body 12 has an inclined nail hole 23 that penetrates acrossthe upper portion of transition body 12 from front surface 20 to rearsurface 18. Inclined nail hole 23 has an incline angle identical to thatof open top surface 21. Inclined nail hole 23 has a nail hole exit 24located immediately below open top surface 21.

Upper body 13 has a top surface 25, a rear vertical surface 26 emergingfrom the open top surface 21 of transition body 12, a rear inclinedsurface 27 projecting upwardly and outwardly from rear vertical surface26, and a substantially vertical front surface 28 flush to front surface20 of transition body 12.

Hanger 1 of present invention as described above also has the followingimportant design features:

(1). An indent 29 is provided at the top surface of upper portion 8 ofbase plate 2 that serves as a visible marking of the vertical centerlineof base plate 2. Lower portion 9 of central section 6 of base plate 2has a slightly greater base plate thickness than that of upper portion8. Lower portion 9 has an inclined top surface 30 emerging outwardly anddownwardly from front surface of upper portion 8. Inclined top surface30 is at the same height of the top surface 22 of left or right sectionof base plate 2, and thus serves as a visible marking of the elevationof open top surface 21 where metal wire of picture frame is loaded upon.The above design features allows user to precisely anchor hanger 1 atdesired location on wall. Increasing base plate thickness in lowerportion 9 of central section 6 of base plate 2 is also necessary inorder to increase the structural strength of hanger 1.

(2). Functionally speaking, upper body 13 forms a front leg of an Uhook, open top surface 21 of transition body 12 forms an internal sideof bottom closed end of U hook, and the upper portion 8 of centralsection 6 of base plate 2 forms a common rear leg of U hooks.

In order to assure that metal wire of picture frame is securely retainedby U hook without possibility of accidentally falling off from U hook orbreaking apart the front leg (i.e. upper body 13), upper body 13 has aheight equal to twice of the lateral width of open top surface 21, and alateral width equal to the lateral width of open top surface 21. Lateralwidth of open top surface 21 is determined by a horizontal distancebetween the rear vertical surface 26 of upper body 13 and the rearsurface 18 of transition body 12.

(3). In order to maximize shear strength of hanger 1, bottom surface 14of lower body 11 has a lateral wall thickness equal to the lateral widthof open top surface 21 of transition body 12, so that shear stress underloading condition can be distributed in the entire vertical crosssection of lower body 11.

(4). Functionally speaking, lower body 11 serves as a bending momentresistant cantilever under loading condition. The design feature (3)above assures that lateral thickness throughout lower body 11 is no lessthan the lateral width of open top surface 21 of transition body 12, andthus maximizes bending strength of hanger 1.

(5). Functionally speaking, transition body 12 serves as a nail anchorbody. Transition body 12 adjacent to nail hole exit 24 and below nailhole 23 is subject to maximum bending stress, and thus needs to bereinforced with greater lateral and vertical wall thicknesses.Accordingly, transition body 12 below nail hole 23 envelopes a circularboundary around nail hole exit 24, which has a radius equal to orgreater than 160% of the lateral width of open top surface 21.

Due to the consideration that front surface 20 of transition body 12serves as a nail striking surface, the front portion of transition body12 has a vertical wall thickness below nail hole 23 that is equal to thelateral width of open top surface 21.

(6). Based on mechanics analyses, maximum load capacity of a wall hangeris determined by the weight load that causes the anchored nail in wallto rotate to a nail pullout angle, and thus causes nail to be pulled outof wall. Before weight load approaches maximum load capacity (as definedabove), load capacity of a hook-above-nail hanger is proportional to thevertical distance between the nail exit point and the bottom edge ofhanger.

Accordingly, in order to maximize load capacity of hanger 1 of presentinvention, nail hole exit 24 is at a predetermined height above thebottom edge 16 of lower body 11, and ratio of “the predetermined heightof nail hole exit 24” to “the lateral width of open top surface 21 oftransition body 11” is about 530%. As confirmed by load testing, at theabove ratio, hanger 1 of present invention achieves a 50 lb. weight loadcapacity when it is anchored to a drywall with two 3d penny size finishnails.

(7). Based on mechanics analyses, the incline angle of anchored nail inwall does not affect nail pullout angle, nor does it affect loadcapacity of hanger. Furthermore, in order to maximize load capacity of ahook-above-nail hanger, the vertical distance between the load landingpoint (i.e. the internal bottom closed end of U hook) and the nail exitpoint needs to be minimized. By specifying the incline angle of open topsurface 21 identical to that of nail hole 23, such a vertical distanceis therefore minimized. Based on the geometry of hanger 1 of presentinvention, the vertical and lateral wall thickness surrounding nail holeexit 24 can be maximized by decreasing incline angle of nail hole 23.When two hangers have an identical size, the hanger with smaller inclineangle has a greater nail exit height above the bottom edge of hanger,and thus has a greater load capacity. But inclined angle of nail hole 23needs to be at least some degrees above a horizontal plane to preventnail from being accidentally pulled out of wall by external force.Accordingly, inclined angle of nail hole 23 is determined at 15 degreethat is significantly less than typical 30 to 45 degree incline angle ofconventional metal hanger.

(8). Hanger body 10 (FIG. 2) has an overall width determined by thegreatest lateral wall thickness in transition body 12, and ratio of “thelateral width of open top surface 21 of transition body 12” to “theoverall width of hanger body 10” is about 50%. This is due to theconsideration that overall width of hanger body 10 needs to besufficiently small to minimize the gap between wall and the top rearsurface of picture frame while hanging the picture frame, but thelateral width of top opening of U hook or the lateral width of open topsurface 21 needs to be sufficiently large to allow metal wire of pictureframe to be easily caught by U hook while engaging metal wire of pictureframe into U hook.

It is understood that some modifications to hanger 1 can be done toenhance the appearance of hanger 1 without affecting its shear/bendingstrength or load capacity. For example, front surface 17 of lower body11, inclined bottom surface 19 and front surface 20 of transition body12, and front surface 28 of upper body 13 can be integrated into acontinuously curved front surface. For another example, bottom surface14 can be an inclined surface rather than a horizontal surface. Thesemodifications are considered within the scope of present invention.

FIG. 3 is a perspective view of the second preferred embodiment ofhanger of present invention, in which, hanger 31 comprises of a baseplate 32 resemble to base plate 2 of first preferred embodiment, a pairof identical left and right lateral projectiles 33 and 34 resemble toleft and right lateral projectiles 3 and 4 of first preferredembodiment, and a third central lateral projectile 35.

As similar to base plate 2 of first preferred embodiment, centralsection 36 of base plate 32 is divided into an upper portion 37 and alower portion 38. Third lateral projectile 35 is integrally connected tothe lower portion 38 along the centerline of base plate 32. Thirdlateral projectile 35 has an inclined nail hole 39 that penetratesacross third lateral projectile 35 from inclined top surface 40 to rearsurface (not shown), and continuously penetrates across base plate 32.

Hanger 31 of second preferred embodiment offers two advantages overhanger 1 of first preferred embodiment. First, as confirmed by loadtesting, hanger 31 offers a greater load capacity at 70 lb. as hanger 31being anchored to drywall with three 3d penny size finish nails. Second,user can install hanger 31 onto wall at desired location by anchoringthe first nail through nail hole 39 of third central lateral projectile35, so that he can adjust hanger 31 to a level position and subsequentlyanchor the second and third nails without holding hanger 31 by hand.Hanger 1 requires user to hold hanger 1 by hand at all time whileinstalling hanger 1 onto wall.

What is claimed is: 1). A wall hanger for hanging a metal wire of apicture frame or the like, which comprises of a base plate, and a pairof identical first and second lateral projectiles integrally connectedto said base plate, wherein: said base plate is divided into a left,central and right rectangular sections, in which, said left section hasa height, width or surface area identical to that of said right section,but smaller than that of said central section, and said central sectionis divided into an upper and lower portions above and below said heightof said left or right section respectively, said first and secondlateral projectiles are integrally connected to front surfaces of saidleft and right sections of said base plate respectively, said first orsecond lateral projectile is integrally connected to said left or rightsection of said base plate to form a hanger body that comprises of alower body, a transition body projecting upwardly and forwardly fromsaid lower body, and an upper body projecting upwardly from the frontportion of said transition body, said lower body has a bottom edge, avertical rear surface emerging from said bottom edge, a bottom surface,and a substantially vertical front surface emerging from said bottomsurface, said transition body has a vertical rear surface flush to saidvertical rear surface of said lower body, an inclined open top surfacesloping upwardly and forwardly from said rear surface, an inclinedbottom surface sloping upwardly and forwardly from said front surface ofsaid lower body, a substantially vertical front surface emerging fromsaid bottom surface, and an inclined nail hole penetrating across anupper portion of said transition body from said front surface to saidrear surface, in which, said inclined nail hole has a about 15 degreeincline angle identical to that of said open top surface of saidtransition body, and said inclined nail hole has a nail hole exitlocated immediately below said open top surface of said transition body,said upper body has a top surface, a lower vertical rear surfaceemerging from said open top surface of said transition body, an upperinclined rear surface sloping upwardly and forwardly from said lowervertical rear surface, and a substantially vertical front surface flushto said front surface of said transition body, said upper body forms afront leg of an U hook, said open top surface of said transition bodyforms an internal side of bottom closed end of said U hook, and saidupper portion of said central section of said base plate forms a commonrear leg of said U hooks, said open top surface of said transition bodyhas a lateral width determined by a horizontal distance between saidrear surfaces of said upper and transition bodies, said hanger body hasan overall width determined by the greatest lateral thickness in saidtransition body, and ratio of “said lateral width of said open topsurface of said transition body” to “said overall width of said hangerbody” is about 50%, said upper body has a height equal to or greaterthan 200% of said lateral width of said open top surface of saidtransition body, and a lateral width at the juncture of said upper andtransition bodies is about equal to said lateral width of said open topsurface of said transition body, said bottom surface of said lower bodyhas the smallest lateral thickness in said lower body, that is equal toor greater than said lateral width of said open top surface of saidtransition body, said transition body below said nail hole envelopes acircular boundary around said nail hole exit, and said circular boundaryhas a radius equal to or greater than 160% of said lateral width of saidopen top surface of said transition body, said front portion of saidtransition body has a vertical wall thickness below nail hole that isequal to or greater than said lateral width of said open top surface ofsaid transition body, said nail hole exit is at a predetermined heightabove said bottom edge of said lower body, and ratio of “saidpredetermined height of said nail hole exit” to “said lateral width ofsaid open top surface of said transition body” is equal to or greaterthan 530%, said base plate has an indent located at a top surface ofsaid upper portion of said base plate that serves as a visible markingof the vertical centerline of said base plate, said lower portion ofsaid base plate has a plate thickness slightly greater than that of saidupper portion of said base plate, and said lower portion of said baseplate has an inclined top surface emerging outwardly and downwardly fromthe front surface of said upper portion of said base plate, which servesas a visible marking of the elevation of said open top surface of saidtransition body where said metal wire of said picture frame is loadedupon. 2). The wall hanger according to claim 1, in which, a thirdlateral projectile is integrally connected to said lower portion of saidcentral section of said base plate along said vertical centerline ofsaid base plate, said third lateral projectile has an inclined nail holewith an incline angle identical to that of said first or second lateralprojectile, and said inclined nail hole penetrates across said thirdlateral projectile and continuously penetrates across said base plate.3). The wall hanger according to claim 1, in which, said bottom surfaceof said lower body is a horizontal bottom surface. 4). The wall hangeraccording to claim 1, in which, said bottom surface of said lower bodyis an inclined bottom surface sloping upwardly and forwardly from saidbottom edge of said lower body. 5). The wall hanger according to claim2, in which, said third lateral projectile has a horizontal bottomsurface. 6). The wall hanger according to claim 2, in which, said thirdlateral projectile has an inclined bottom surface sloping upwardly andforwardly from the bottom edge of said third lateral projectile.